The present disclosure relates to digital printing and particularly relates to printing jobs where it is desired to print documents having consecutively numbered or sequenced pages or sheets and more particularly relates to such printing jobs where delivery of the printed sheets is scheduled for plural destinations. For example, where the print job requires multiple copies of a document having a large number of sequentially numbered pages, it may be necessary to deliver the printed documents to different receptacles or stackers when the initial receptacle or stacker is filled before the print job is complete.
Such printing jobs are commonly encountered where documents with a large number of pages are required in great numbers for mass distribution such as, for example, to a large number of employees or for marketing or advertising purposes.
Digital printing engines have become quite efficient and capable of increased volume and productivity (i.e. printing speed) since the advent of xerographic, ink jet and laser printing. However, these printing engines all require mechanisms capable of handling and transporting individual sheets of print media at relatively high speeds; and, despite the sophistication of the sheet handling mechanisms, often incur a fault condition in the printing process or jamming of the paper during transporting of the paper in the print engine or feeding of the sheets into or out of the print engine.
Where a fault occurrence or jamming occurs during the printing of a document having a large number of sequentially numbered pages, the operator must stop the printing and clear the fault condition before printing can be resumed. Heretofore, when printing was resumed after fault clearance, it was resumed at the page in the numbered sequence where the fault occurred. In many cases, the print engine may have delivered printed sheets having later numbers in the sequence before the fault occurred; and, these later numbered sheets must also be removed and are duplicated upon resumption of the printing after fault clearance. Thus, the duplication of the sheets creates a waste of print media and printing ink which results in a lower overall productivity to the printing process.
Therefore, it has been desired to provide a way or means of eliminating the duplication of sequentially numbered print media sheets upon resumption of printing after a fault clearance in a digital image printing engine.
Furthermore, modern digital printing engines are capable of scheduling the sequencing of different documents for simultaneously printing in the print engine where the pages of the different documents may be interleaved in the output of the print engine to the receptacle or stacker. Thus, although the pages of each of the different documents are sequentially numbered, the finished sheets in the receptacle or stacker may not be sequential for a given document but from one sheet to the next in the stack may be for different documents. Thus, upon occurrence of a fault condition and clearance of the fault some of the sheets in the stack may be delivered after the fault condition but relate to a different document than that involved in the fault condition. Upon resumption of printing after fault clearance, later delivered sheets relating to different document may be unnecessarily discarded. Thus, it has been desired to provide a way of preventing the needless reprinting of pages not out of sequence and not of the same type or class of document upon resumption of printing after fault clearance.